Inductance



1930- R. RAMSDELL INDUCTANCE Filed March 15. 1929 [H g g F 1 K E1 1 2 INVENTOR z r/qyz- @BY 22K;

W [1,, AT NEY Patented Nov. 25, 1939 uurreo STATES PATET OFFICE RUSSELL RAMSDELL, 0F lOUGHKEEPSIE, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MEN'rs, 'ro PILOT-RADIO. & roien'oosro A. CORPORATION OF DELAWARE sA rion, or LAWRENCE, MASSACHUSETTS,

rNnUo'rANoE Application filed March 13,

My invention relates to radio apparatus andniore particularly to an improvement in tubes or cylinders, adapted to support the primary and secondary windings of a transformer.

In the winding of the primary and secondary coils of an air core transformer, it is the usual practice to split the secondary and place the two secondary coil sections upon both sides of the primary. The two secondary sections are hrst wound on a tube or insnlatmg material, being so positioned thereon as to leave sufiicient space therebetween for the primary coil. The tube is drilled or otherwise aperture-d adjacent the inner or opposing ends of the two secondary sections and the free ends thereof run through these apertures to the interior of the tube. These ends are then connected, as by soldering Tit-hill the tube. The primary coil is then wound on the portion of the tube between the sections, the ends of the primary and secondary coils, be? ing connected to suitable binding posts. If desired, the primary is first wound on the tube and then the secondary, the two sections of the latter being connected d This known method of winding the ondi y sections on the tube has sererr advantages. in the first place, it that the secondary coil wire be cut center in order that the ends thereof, which formed the adjacent ends of the secondary sections, might be passed through the apertures in the tube. This consumed both time and labor. Secondly, the danger of the windings becoming loose was greatly increased cause of the necessity of cutting the wire and be :ause of the increased amount of handling of the transformer before the ends of the wires were finally fixed. And finall the connection within the tube between the adjacent ends of the secondary sections not only added another step to the process of winch ing the transformer but introduced an additional source of loose or imperfect contacts.

It is an object of the present invention to overcome the disadvantages above mentioned, and to provide a tube which is so constructed that the two sections of a split secondary may be wound thereon continuously, that is, with- 1929' Serial No. 346,568.

out being cut at the center and without interrupting such winding, there being left an unobstructed space, as before, for the primary winding. I accomplish such object by p oviding a slot across the space to be occupied by the primary of such form and in such manner that a straight line drawn between the ends of the slot crosses a rigid part of the tube or an abutment connected to the tube, so that a loop of wire inserted into the slot and pulled across the same so as to engage in the ends of the slot will cross such rigid part or abutment and be prevented from slipping out of the slot. In this manner, I enable the winding 01" the secondary to be greatly facilitated and insure a tight and, continuous coil.

in the accompanying drawing, 1 show by way of example, a preferrel form of my invention, Figure 1, showing a view oi a tube, constructed in accordance with my invention and having a primary and a split secondarv woundthereon, and Figure 2, beiu View of the tube with the windings removec.

' Figure 1, shows a tube 10, of balzelite or other insulating material having wound thereon a primary 11 and the sections 12 and 13 of the secondary, the whole forming a Well-known type of air transformer. The ends of the primary are connected to the binding posts or terminal lugs 14 and 15, while the outer ends of the secondary sections are connected to the terminal lugs 16 and 17. k

In accordance with my invention, I pro vide in the tube across the portion occupied by the primary 11, a curved slot which in the embodiment illustrated is in the form of the letter S as shown at 18. There are thus provided two abutments 19 and 20, which overlap to a certain extent, so that a straight line drawn between the ends of the slot-Will cross'both these abutments.

. In Winding the secondary of a transform or on my improved tube, the section 12 is first wound, the free end of the wire being first passed through the hole 21 and connected to the terminal lug 16. The section is then Wound until the last turn 22 is reached. The Wire is thenheld'tightly against the ice tube 10 with one hand, while a loop is formed of the wire with the other hand and passed into the slot, preferably at the middle portion thereof. The. ends of the loop are'then moved toward the opposite ends of the slot, while the loop portion 23, engages underneath the abutments 19 and 20 inside the .tube. The wire is then stretched tight and the winding of the second section 13', proceeded with. It will be evident that the abutments 19 and 20, keep the loop 23 permanently in place and prevent disengagement thereof, from the slot 18. The winding of the secondaryis thus greatly simplified and brokencontacts or loose winding 7 prevented.

' threaded into the slot and-made to span the Vhile I have shown a slot in the form an 8, it will be clear that other curves may to have a primary between asplit secondary wound thereon, and having a curved slot therein, whose ends are located at opposite sides of the zone designed to be occupied by V the primary and abutments formed in said slot for holding a loop of wire, forming part of and connecting the respective parts of the secondary. V I

4. A tube of insulating material adapted to have a primary between a split secondary V wound thereon, and having an 8-slot there- 111, whose ends are located at opposite sides of the zone designed to be occupied by the primary and abutments formed in said slot fol-holding a loop of wire forming part of the secondary in said slot.

. RUSSELL RAMSDELL.

be employed, such as a U 'or a J-s1ot.. Furslot, so that when the Wireis drawn tight,

' it will hold the abutment against the inner face of the tube, the abutmentat the same time preventing escape of the loop from the slot. Such abutment may be pivoted to the tube adjacent the slot as the innerface of such tube. V

be composed of both curved and r and I wish it to be under-v It is. obvious that various changes and 1 modifications may be made to the details of construction without departing 7 from the v general spirit of the invention set forth in the appended claims.

It will beobvious, for instance, thatmy improved tube may be used for, tra sf rm ers having a single secondary section and a splitprimary, or a single secondary ora single primary.

I claim: r

1. A tube'of insulating material, adapted I to have ajprimary and a split secondary wound thereon and having a slot extending across the Zone designed to be occupied by the primary and abutments' formed insaid slot, serving to carry a portion of a loop of wire interconnecting the respective parts of the split secondary.

' 2; A tube of insulating material," adapted to have a primary between a split secondary wound thereon a slot in said tube, extending acrossthe zone designed tov bemc'upi a the primary, and 'abutments adapted to retain in said slot, a loop of interconnecting:

wire leading from one part ofthe split sec- V ondary, under the primary, to the otherpart" of said secondary. V

3. A tube of: insulating material: adapted 

